Wise Young0:03
I've been working on spinal cord injury now for over 40 years, and been told by almost everybody that nothing could be done.
The spinal cord connects the brain to the body. When you disconnect, everything below the injury point disappears. When there's been an injury, most spinal cords simply have had a transient compression of the spinal cord. That's what we call a contusion. What happens is that the spinal cord is squeezed away from the compression site, and the nerve fibers are like rubber bands. If they've been pulled apart at a certain speed, they break.
Very early on, I developed a rat model of spinal cord injury. The first thing we found was that you only need about 10% of the fibers in the spinal cord for an animal to recover walking. So what we saw in animals is true in humans, and that gave me hope because if we only had to regenerate 10% of the spinal cord, I mean, it's doable.
At the time when we started doing this, there were already about 30 laboratories that had reported that in rats, if you gave umbilical cord blood mononuclear cells, which are a fraction of the cord blood that have the stem cells, we transplant them into the spinal cord of the rats and the rats recovered walking. So that's when I decided to try to do this in humans.
Spinal cord injury is a relatively rare phenomenon in the United States. Only about 10,000 people per year get spinal cord injury. But in China, about 80,000 people get spinal injured every year. And we decided to go after the cases that have the least amount of hope, and these are people long time after injury who have complete spinal cord injury, loss of all function below the injury site, and have not walked for several years.
We inject the cells into the normal part of the spinal cord, not the injured part. And what we discovered was that the cells we transplanted will migrate into the injury site and build a bridge. And then the axons follow. They grow no faster than about a millimeter a day. And so it takes, you know, to grow from your neck down to the lower part of your spinal cord will take over a year. You just have to be patient. Plus you have to walk, you have to use it. If you don't use the regenerated fibers or the connections, it's gone. It doesn't come back. And so the exercise turns out to be a critical factor in the recovery in our clinical trial.
In Chinese, the word six is liù. And so I called this the liù liù liù program, which means that the patients are walking six hours a day, six days a week, for six months. And given that 15 out of 20 patients that we transplanted recovered walking and bowel and bladder function. Many of our patients are doing their shopping. They can transfer from bed to wheelchair. Transfer from wheelchair into the car, you know, without any help. They don't need somebody to do everything for them. And to them, this is more important and more valuable than being able to walk. Many of them just want to be independent.
Part of our goal right now is to replicate this around the world. So we've applied to the U.S. FDA, and they want us to redo all the animal studies. And this is because, you know, the FDA is very careful and they said, 'Well, you know, you use cells from another cord blood bank. Therefore you have to test the particular cord blood bank that you will be using for the trial.' The body can recognize foreign cells when they're injected into it. And that's why when you do a kidney transplant or something, you have to match something called HLA, so that they will not be immune rejected. Since the FDA wants us to use human cells in rats, we have to use RNU rats. Now, these rats are essential for what we do. All cell transplant studies require these animals. I'm very grateful to Charles River. I mean, it took a big investment on their part to create this line of animals. This allows the entire field of cell transplantation to be carried out, you know, for testing human cells in animals. Based on these studies, we're able to go to human clinical trials. I want to use this to get ourselves into a pivotal phase three trial that will be done around the world and get approval by the end of 2024 for this therapy.
So one of the reasons why I really worked very hard for 40 years to do clinical trials was to give hope, because if we had therapies that did help some people, that this would give them hope. And I think now we have.
